Feedback

Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or occurrences of the same (i.e. same defined) event / phenomenon (or the continuation / development of the original phenomenon) in the present or future. When an event is part of a chain of cause-and-effect that forms a circuit or loop, then the event is said to "feed back" into itself.
Feedback is also a synonym for:

• Feedback signal - the information about the initial event that is the basis for subsequent modification of the event
• Feedback loop - the causal path that leads from the initial generation of the feedback signal to the subsequent modification of the event
• Audio feedback - the special kind of positive feedback that occurs when a loop exists between an audio input and output.